Union select null, null, null, null, null, null, null from information_schema.tables. for a small database containing three tables. this instruction is used in sql injection I tried it and it worked but I didn't really know how it works can somebody help me...
(M): SELECT CONCAT(login, password) FROM members. 7. Строки без кавычек Есть несколько
Hours 1 1 2 null null null. The result must be: 3. My query is: select count(distinct hour) from hours; but it returns: 2. I tested also
Since a NULL concatenated with a string yields a NULL, we can attempt to build our sub-string and replace a NULL with an empty string, which is then concatenated to the next part of the name. This assumes that FirstName and Surname are always NOT NULL, but you could apply the same logic to...
SELECT m.id, m.name, m.description, m.directions, COUNT(j.markerid) as marker_jingles FROM markers AS m LEFT OUTER JOIN jingles AS j ON j.markerid=m.id WHERE 1. But am a bit stuck because I cannot figure out how to get it to return rows when the COUNT is 0.
UNION ALL SELECT NULL, *, NULL, NULL FROM email. I understand what this does and why; the hacker needs to create a query that has the same number
http://www.indianamri.com/index.php?page=Indiana_MRI_Bloomington_-_MRI_Services_for_Bloomington_and_Southern_Indiana_Magnetic_Resonance_Imaging&menu_id=1'+limit+0+UNION+SELECT+1,concat_ws(0x3a,user(),version(),database())+
returns non null values in group */ SELECT COUNT(Col1) FROM ##TestData; Because of this, COUNT, DISTINCT, and NULLs have a special relationship with each other
Существуют специальные операторы IS NULL и IS NOT NULL, которые позволяют производить сравнения с NULLами.
· Using SELECT COUNT(*) or SELECT COUNT(1) (which is what I prefer to use) will return the total of all records returned in the result set regardless of NULL values. · Using COUNT()will count the number of non-NULL items in the specified column (NULL fields will be ignored).